Polymeric fluorescent substance and polymer light-emitting device using the same

Abstract

A polymeric fluorescent substance showing fluorescence in the solid state, having a polystyrene reduced number-average molecular weight of 10 3 to 10 8 , and comprising one or more repeating units of formula (1) and one or more repeating units of formula (2) which is different from formula (1), exhibits strong fluorescence and/or excellent charge transporting property, and a high performance polymer LED which can be driven at low voltage and high efficiency is obtained.

1. A polymeric fluorescent substance showing fluorescence in the solid state and having a polystyrene reduced number-average molecular weight of 10 3  to 10 8 , wherein the substance is a random copolymer and contains one or more repeating units of formula (1) and one or more repeating units of formula (2), and the total amount of repeating units of formula (1) is 10 mol% or more and 90 mol% or less based on the total amount of repeating units of formulae (1) and (2): 
       
         
           
           
               
               
           
         
         wherein, R 1 , R 2 , R 3  and R 4  represent each independently a hydrogen atom or a substituent, and at least one of R 1 , R 2 , R 3  and R 4  is a group selected from the group consisting of alkoxy groups, aryl groups substituted with an alkoxy group, aryloxy groups and arylalkoxy groups,
   —Ar 1 —  (2) 
 
         wherein, Ar 1  represents a different group from that of formula (1) and is a group selected from the group consisting of repeating units of formula (8): 
       
       
         
           
           
               
               
           
         
       
       wherein, R 13  and R 16  represent each independently a group selected from the group consisting of alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, alkylthio groups having 1 to 20 carbon atoms, alkylsilyl groups having 1 to 60 carbon atoms, alkylamino groups having 1 to 40 carbon atoms, aryl groups having 6 to 60 carbon atoms, aryloxy groups having 6 to 60 carbon atoms, arylsilyl groups having 6 to 60 carbon atoms, arylamino groups having 6 to 60 carbon atoms, arylalkyl groups having 7 to 60 carbon atoms, arylalkoxy groups having 7 to 60 carbon atoms, arylalkylsilyl groups having 7 to 60 carbon atoms, arylalkylamino groups having 7 to 60 carbon atoms, arylalkenyl groups having 8 to 60 carbon atoms, arylalkynyl groups having 8 to 60 carbon atoms, monovalent heterocyclic compound groups having 4 to 60 carbon atoms and a cyano group; c and d represent each independently an integer of 0 to 4; when c is 2 or more, a plurality of R 13 s may be the same or different; when d is 2 or more, a plurality of R 16 s may be the same or different; wherein one or two of substituents on a benzene ring are groups selected from the group consisting of alkoxy groups, aryl groups substituted with an alkoxy group, aryloxy groups and arylalkoxy groups, R 14  and R 15  represent each independently a group selected from the group consisting of a hydrogen atom, alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 60 carbon atoms, arylalkyl groups having 7 to 60 carbon atoms, monovalent heterocyclic compound groups having 4 to 60 carbon atoms and a cyano group; R 13  to R 16  may be connected to form a ring; and when R 13  to R 16  are a group containing an alkyl chain, one or more of a methyl group, a methylene group and a methine group constituting the alkyl chain may be substituted with a group containing a hetero atom; and formula (12): 
       
         
           
           
               
               
           
         
       
       wherein, Ar 5  represents an arylene group or a divalent heterocyclic compound group; R 24  and R 29  represent each independently a group selected from the group consisting of alkyl groups having 1 to 20 carbon atoms, alkoxy groups having 1 to 20 carbon atoms, alkylthio groups having 1 to 20 carbon atoms, alkylsilyl groups having 1 to 60 carbon atoms, alkylamino groups having 1 to 40 carbon atoms, aryl groups having 6 to 60 carbon atoms, aryloxy groups having 6 to 60 carbon atoms, arylsilyl groups having 6 to 60 carbon atoms, arylamino groups having 6 to 60 carbon atoms, arylalkyl groups having 7 to 60 carbon atoms, arylalkoxy groups having 7 to 60 carbon atoms, arylalkylsilyl groups having 7 to 60 carbon atoms, arylalkyamino groups having 7 to 60 carbon atoms, arylalkenyl groups having 8 to 60 carbon atoms, arylalkynyl groups having 8 to 60 carbon atoms, monovalent heterocyclic compound groups having 4 to 60 carbon atoms and a cyano group; q and r represent each independently an integer of 0 to 4; when q is 2 or more, a plurality of R 24 s may be the same or different; when r is 2 or more, a plurality of R 29 s may be the same or different; R 25  to R 28  represent each independently a group selected from the group consisting of a hydrogen atom, alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 60 carbon atoms, arylalkyl groups having 7 to 60 carbon atoms, monovalent heterocyclic compound groups having 4 to 60 carbon atoms and a cyano group; R 24  to R 29  may be connected to form a ring; and when R 24  to R 29  are a group containing an alkyl chain, one or more of a methyl groups, a methylene group and a methine group constituting the alkyl chain may be substituted with a group containing a hetero atom. 
     
     
       2. The polymeric fluorescent substance according to  claim 1  wherein the repeating unit of formula (1) is selected from the group consisting of repeating units of formulae (4) and (5): 
       
         
           
           
               
               
           
         
       
       wherein, R 5  represents a group selected from the group consisting of alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 60 carbon atoms, arylalkyl groups having 7 to 60 carbon atoms and monovalent heterocyclic compound groups having 4 to 60 carbon atoms; n represents an integer of 1 to 4; and when n is 2 or more, a plurality of OR 5 s may be the same or different, 
       
         
           
           
               
               
           
         
       
       wherein, R 6  and R 7  represent each independently a group selected from the group consisting of alkyl groups having 1 to 20 carbon atoms, aryl groups having 6 to 60 carbon atoms, arylalkyl groups having 7 to 60 carbon atoms and monovalent heterocyclic compound groups having 4 to 60 carbon atoms; 1 represents an integer of 1 to 5, m represents an integer of 1 to 3; and when 1 is 2 or more, a plurality of OR 6 s maybe the same or different; and when m is 2 or more, a plurality of OR 7 s may be the same or different. 
     
     
       3. The polymeric fluorescent substance according to  claim 1  or  2  wherein the repeating unit of formula (2) is selected from the group consisting of repeating units of formula (8). 
     
     
       4. The polymeric fluorescent substance according to  claim 1  or  2  wherein the repeating unit of formula (2) is selected from the group consisting of repeating units of formula (12). 
     
     
       5. A polymer light emitting device comprising a pair of electrodes composed of an anode and a cathode at least one of which is transparent or semitransparent and at least one light emitting layer comprising a polymeric fluorescent substance according to any one of  claims 1  or  2  disposed between the electrodes. 
     
     
       6. The polymer light emitting device according to  claim 5  wherein a layer comprising a conducting polymer is disposed at least between one electrode and the light emitting layer such that the layer comprising a conducting polymer is adjacent to said electrode. 
     
     
       7. The polymer light emitting device according to  claim 5  wherein an insulation layer having a thickness of 2 nm or less is disposed at least between one electrode and the light emitting layer such that the insulation layer is adjacent to said electrode. 
     
     
       8. The polymer light emitting device according to  claim 5  wherein a layer comprising an electron transporting compound is disposed between the cathode and the light emitting layer such that the layer comprising an electron transporting compound is adjacent to said light emitting layer. 
     
     
       9. The polymer light emitting device according to  claim 5  wherein a layer comprising a hole transporting compound is disposed between the anode and the light emitting layer such that the layer comprising a hole transporting compound is adjacent to said light emitting layer. 
     
     
       10. The polymer light emitting device according to  claim 5  wherein a layer comprising an electron transporting compound is disposed between the cathode and the light emitting layer such that the layer comprising an electron transporting compound is adjacent to said light emitting layer, and a layer comprising a hole transporting compound is disposed between the anode and the light emitting layer such that the layer comprising a hole transporting compound is adjacent to said light emitting layer. 
     
     
       11. A flat light source comprising a polymer light emitting device according to  claim 5 . 
     
     
       12. A segment display comprising a polymer light emitting device according to  claim 5 . 
     
     
       13. A dot matrix display comprising a polymer light emitting device according to  claim 5 . 
     
     
       14. A liquid crystal display comprising a polymer light emitting device according to  claim 5  as a back-light.